Year	% of total fuel combustion
1990	26.438296003513393
1991	22.809593734703867
1992	20.375939849624057
1993	16.122448979591837
1994	7.849293563579278
1995	25.112107623318387
1996	21.3381555153707
1997	23.333333333333332
1998	21.328671328671327
1999	24.458874458874455
2000	19.101123595505616
2001	23.670212765957448
2002	16.455696202531644
2003	17.870722433460077
2004	22.736030828516373
2005	22.290388548057262
2006	23.770491803278688
2007	29.36241610738255
2008	27.960057061340944
2009	34.815950920245406
2010	32.78145695364238
2011	38.41886269070735
2012	41.06583072100313
2013	44.369369369369366
2014	27.751196172248804